The longterm objective of these researches is reduction of the incidence of sudden coronary death. The immediate goals are 1) to elucidate the degree and the nature of relationships between ectopic cardiac rhythms and coronary death and 2) to determine whether ectopic activity can be safely modified by intervention on living habits. Premature ventricular complexes (PVC) are clearly related to short and longterm risk of sudden death in patients after myocardial infarction. Evidence about the relationship in general populations is conflicting and requires more detailed study, proposed here in available data from large longitudinal population studies. Preventive efforts are hampered by lack of a sufficiently safe and effective anti-arrhythmic agent. This proposal includes study of the influence of systematic intervention on common habits related to catecholamine levels and myocardial excitability. These include consumption of caffeine, nicotine and alcohol, and habits of sleep and physical activity. Eligible subjects will be detected from monitoring at the primary screening station of an existing NHLI collaborative study (MRFIT) and volunteers having consistently frequent PVC will be randomly assigned to control and intervention groups of a "hygienic" preventive trial. Information provided by this project on the association of PVC and death, and the influence of intervention, should provide a guide about the potential for future definitive preventive efforts.